package de.rtlsdr.utils;

/*
 * taken from google-tv-pairing-protocol
 * https://code.google.com/p/google-tv-pairing-protocol/
 * original java package was com.google.polo.pairing
 */

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class HexDump {

  private final static char[] HEX_DIGITS = {
    '0', '1', '2', '3', '4', '5', '6', '7',
    '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
  };

  public static String dumpHexString(byte[] array) {
    return dumpHexString(array, 0, array.length);
  }

  public static String dumpHexString(byte[] array, int offset, int length) {
    
    StringBuilder result = new StringBuilder();
    byte[] line = new byte[16];
    int lineIndex = 0;

    result.append("0x");
    result.append(toHexString(offset));

    for (int i = offset; i < offset + length; i++) {
      if (lineIndex == 16) {
        result.append(" ");

        for (int j = 0; j < 16; j++) {
          if (line[j] > ' ' && line[j] < '~') {
            result.append(new String(line, j, 1));
          } else {
            result.append(".");
          }
        }

        result.append("\n0x");
        result.append(toHexString(i));
        lineIndex = 0;
        
      }

      byte b = array[i];
      result.append(" ");
      result.append(HEX_DIGITS[(b >>> 4) & 0x0F]);
      result.append(HEX_DIGITS[b & 0x0F]);

      line[lineIndex++] = b;
    }

    // if (lineIndex != 16) { // ???
      
      int count = (16 - lineIndex) * 3;
      count++;
      for (int i = 0; i < count; i++) {
        result.append(" ");
      }

      for (int i = 0; i < lineIndex; i++) {
        if (line[i] > ' ' && line[i] < '~') {
          result.append(new String(line, i, 1));
        } else {
          result.append(".");
        }
      }
      
    // } // ???

    return result.toString();
    
  }

  public static String toHexString(byte b) {
    
    return toHexString(toByteArray(b));
    
  }

  public static String toHexString(byte[] array) {
    
    return toHexString(array, 0, array.length);
    
  }

  public static String toHexString(byte[] array, int offset, int length) {
    
    char[] buf = new char[length * 2];
    int bufIndex = 0;
    
    for (int i = offset; i < offset + length; i++) {
      
      byte b = array[i];
      buf[bufIndex++] = HEX_DIGITS[(b >>> 4) & 0x0F];
      buf[bufIndex++] = HEX_DIGITS[b & 0x0F];
      
    }

    return new String(buf);
    
  }

  public static String toHexString(int i) {
    
    return toHexString(toByteArray(i));
    
  }

  public static byte[] toByteArray(byte b) {
    
    byte[] array = new byte[1];
    array[0] = b;
    return array;
    
  }

  public static byte[] toByteArray(int i) {
    
    byte[] array = new byte[4];

    array[3] = (byte) (i & 0xFF);
    array[2] = (byte) ((i >> 8) & 0xFF);
    array[1] = (byte) ((i >> 16) & 0xFF);
    array[0] = (byte) ((i >> 24) & 0xFF);

    return array;
    
  }

  private static int toByte(char c) {
    
    if (c >= '0' && c <= '9') return (c - '0');
    if (c >= 'A' && c <= 'F') return (c - 'A' + 10);
    if (c >= 'a' && c <= 'f') return (c - 'a' + 10);
    throw new RuntimeException("Invalid hex char '" + c + "'");
    
  }

  public static byte[] hexStringToByteArray(String hexString) {
    
    int length = hexString.length();
    byte[] buffer = new byte[length / 2];

    for (int i = 0; i < length; i += 2) {
      buffer[i / 2] = (byte) ((toByte(hexString.charAt(i)) << 4)
          | toByte(hexString.charAt(i + 1)));
    }

    return buffer;
    
  }

}
